Generally yes. Sometimes you run into complications such as not enough space in the box to connect up the new wires coming in.
Original BX cable is not code compliant. Its spiral sheath is not a good and sufficient ground. Nowadays, most spiral wrapped cabling must have a straight grounding strip or wire running through it.
When cleaning anything including baby diapers, it is better to sweep off or scrape off as much solid and semisolid material as you can first. (1) Less cleaning fluid or detergent needs to be used, (2) Less of a mushy mess which in turn means that bleaches or disinfectants will be more effective.